Eye (2010) 24, 101–106 & 2010 Macmillan Publishers Limited All rights reserved 0950-222X/10 $32.00 www.nature.com/eye 1 1 2 Influence of size of K Hayashi , F Nakao and H Hayashi CLINICAL STUDY neodymium:yttrium- aluminium-garnet laser posterior capsulotomy on visual function Abstract Introduction Purpose The aim of this study was to It has been shown that posterior capsule examine the influence that the size of a opacification (PCO) following cataract surgery neodymium:yttrium-aluminium-garnet disturbs various visual functions, including (Nd:YAG) laser capsulotomy performed visual acuity (VA), contrast sensitivity and glare for posterior capsule opacification (PCO) disability, although controversy still remains as has on visual acuity (VA), and on contrast to which function is impaired most prominently VA and that in the presence of glare due to PCO.1–9 However, we believe that the (glare VA). impairment of visual functions is related to the Methods A total of 41 consecutive eyes with degree of PCO. In eyes with dense PCO that PCO first underwent Nd:YAG laser require neodymium:yttrium-aluminium-garnet capsulotomy of smaller than pupillary size, (Nd:YAG) laser posterior capsulotomy, as all after which the capsulotomy was secondarily visual functions are impaired, VA is associated 1Hayashi Eye Hospital, enlarged, 2 weeks later, to greater than most strongly with the degree of PCO.7 When Fukuoka, Japan pupillary size. Best-corrected VA, and contrast the PCO is slight, however, contrast sensitivity 2 VA and glare VA under photopic and mesopic or glare disability deteriorates with no marked Department of Ophthalmology, School of conditions were measured after the small and loss of VA.8 Medicine, Fukuoka large capsulotomies were made. Nd:YAG laser posterior capsulotomy University, Fukuoka, Japan Results After enlargement, the mean improves these visual functions. However, capsulotomy area increased significantly from surgeons are often perplexed about what size of Correspondence: K Hayashi, 4.8 to 15.3 mm2 (Po0.0001). Best-corrected VA capsulotomy should be made. When a large Department of did not improve significantly after capsulotomy is made, adverse effects of the Ophthalmology, Hayashi Eye Hospital, enlargement (P ¼ 0.1282). However, photopic Nd:YAG capsulotomy, such as retinal 4-7-13 Hakataekimae, 10–12 12,13 contrast VA and glare VA at moderate to low detachment, cystoid macular oedema or Hakata-Ku, contrast visual target before enlargement were a rise in intraocular pressure (IOP),14,15 tend to Fukuoka 812, significantly worse than those after occur. On the other hand, if the capsulotomy is Japan enlargement (Pp0.0242); furthermore, mesopic too small, visual function may not be recovered. Tel: þ 81 92 431 1680; Fax: þ 81 92 441 5303. contrast VA and glare VA improved Indeed, previous studies showed that glare E-mail: hayashi-ken@ significantly after enlargement (Pp0.0431). disability in eyes with a small capsulotomy is hayashi.or.jp Conclusion Contrast VA and glare VA with a worse than those with a large capsulotomy small capsulotomy were significantly worse despite no significant difference in VA.16–18 Received: 18 November than those with a large capsulotomy, which However, to date, there is no study about the 2008 suggests that a capsulotomy larger than the relationship between capsulotomy size and Accepted in revised form: 31 January 2009 pupillary size is necessary to restore contrast contrast sensitivity. Published online: 6 March sensitivity and glare disability. The aim of the study described herein was 2009 Eye (2010) 24, 101–106; doi:10.1038/eye.2009.41; to examine the influence of Nd:YAG laser published online 6 March 2009 capsulotomy size on VA, and on contrast The authors have no sensitivity with and without glare. Because proprietary interest in any of the materials mentioned in Keywords: neodymium:yttrium-aluminium- contrast sensitivity and glare disability varies this article and have garnet laser capsulotomy; visual acuity; contrast substantially from patient to patient, we made received no financial sensitivity; glare disability the Nd:YAG laser posterior capsulotomy of support. Size of Nd:YAG capsulotomy and visual function K Hayashi et al 102 smaller and larger than the papillary size in one eye, and Outcome measures the visual function was strictly compared between the Best-corrected VA on decimal charts, and contrast VA eyes with small capsulotomy and those with large and that in the presence of a glare source (glare VA) were capsulotomy. measured at 2 weeks after the first capsulotomy and at 2 weeks after the enlargement. Contrast VA and glare VA Patients and methods were examined using the Contrast Sensitivity Accurate Tester (CAT-2000; Menicon, Tokyo, Japan).8 This device Patients measures the logarithm of the minimal angle of All pseudophakic patients who were consecutively resolution (logMAR) VA using five contrast visual targets scheduled for Nd:YAG laser posterior capsulotomy (100, 25, 10, 5 and 2.5%) under photopic and mesopic between May 2007 and July 2008 were screened for conditions. Measurement under photopic conditions was 2 inclusion in this study. An Nd:YAG laser capsulotomy made with chart lighting of 100 cd/mm , and that under was scheduled when an eye lost two or more decimal the mesopic conditions was done with chart lighting of 2 lines of VA or when the patient complained of blurred 3 cd/mm . A glare light source of 200 lux was located in 1 vision. One of the authors (KH) verified the presence of the periphery at 20 along the visual axis. definite PCO on slit-lamp biomicroscopy and also The area of the Nd:YAG capsulotomy opening was performed patient screening. When both eyes were measured using the Scheimpflug photography system affected, only the eye that was scheduled for Nd:YAG (EAS-1000; Nidek) at 2 weeks after the small capsulotomy first was screened. Pre-laser exclusion capsulotomy was created and at 2 weeks after its criteria were any pathology of the macula or optic nerve, enlargement. The refractive status (spherical and previous history of inflammation, severe contraction of cylindrical powers) and keratometric cylinder were the anterior capsule or liquefied after-cataract. Eyes of measured using an auto-refractometer (KR-7100; Topcon, diabetic patients and of long axial length were not Tokyo, Japan). The manifest spherical equivalent was excluded. Post-laser exclusion criteria were best- determined as the spherical power plus half the corrected VA of o0.5 due to any pathology of unknown cylindrical power. The pupillary diameter under cause, media opacities other than PCO and any photopic and mesopic conditions was examined using an difficulties with data collection or analysis. A total of 45 electronic pupillometer (FP-10000; TMI, Saitama, Japan). eyes of 45 patients who met the inclusion criteria were The central retinal (foveal) thickness was measured using identified and recruited. The study protocol was the Stratus optical coherence tomography-3 (OCT-3; Carl approved by the institutional review board. Informed Zeiss Meditec, Dublin, CA, USA). IOP was measured by consent was obtained from each patient, and the study the same surgeon (FN) using an applanation tonometer was conducted in accordance with the tenets of the before and at 2 h after the Nd:YAG laser capsulotomy. All Declaration of Helsinki Principles. other measurements were made by ophthalmic technicians who were not aware of the purpose of this study. Laser procedures A surgeon (FN) first made an Nd:YAG laser capsulotomy Statistical analysis of smaller than the pupillary diameter using a Q-switched Nd:YAG laser (YC-1300; Nidek, Gamagori, Decimal VA was converted to a logMAR scale for Japan). After topical anaesthesia, a contact lens was statistical analysis. Contrast VA and glare VA were also applied to enhance power density at the level of the converted to the logarithm of inverse values for statistical posterior capsule. The central posterior capsule within analysis. Best-corrected VA, contrast VA and glare VA, the pupillary area was cleared as much as was possible area of the anterior capsule opening and other without pupil dilation by emitting laser energy on the continuous variables before and after enlargement of posterior capsule; energy levels were between 0.5 and the capsulotomy opening were compared using the 1.5 mJ. Special care was taken to not to pit the intraocular Wilcoxon signed-rank test. Any differences showing lens (IOL) optic. a P-value of o0.05 were considered to be statistically At approximately 2 weeks after the first capsulotomy, significant. after full pupil dilation, the capsulotomy opening was enlarged to greater than the pupillary area Results (approximately 5.0 mm in diameter) by the same surgeon who used almost the same technique as was used for the Of the 45 eyes of 45 patients originally enrolled, 4 eyes smaller capsulotomy. were excluded: 2 patients refused to undergo two-step Eye Size of Nd:YAG capsulotomy and visual function K Hayashi et al 103 Table 1 Patient characteristics significantly better than those before enlargement (P 0.0242), although no significant difference was found Characteristics After small After large P-value p capsulotomy capsulotomy at high contrast visual targets. Under mesopic conditions (Figure 2), contrast VA and glare VA at high to moderate ± F Age 74.1 8.0 visual targets improved significantly after enlargement to Gender (M/F) 9/32 F the large capsulotomy (Pp0.0136), but no significant Left/right 17/24 F SE (D) À0.90±0.90 À1.02±0.87 0.0897a difference was found in the contrast VA and glare VA at low contrast visual target primarily because it was Keratometric immeasurable in most of the patients (Figure 2). ± ± a Cylinder (D) 0.86 0.55 0.83 0.55 0.4468 After both small and large capsulotomies, no significant correlation was found between the opening Pupillary diameter (mm) Photopic 2.47±0.43 2.68±0.69 0.0208b area created by the capsulotomy and best-corrected VA, Mesopic 3.43±0.76 3.62±0.69 0.1504a and between the opening area and the contrast VA or glare VA.